Biobased Polyols for Industrial Polymers

Deny Kyriacos

• Publisher: Wiley-Scrivener
• Year: 2020
• Print ISBN:
  9781119620167
• Edition: 1
• eBook ISBN:
  9781119620297
• Topic: Technology & Engineering
• Subtopic: Chemical & Biochemical Engineering
• Index: Technology & Engineering

The replacement of polyols synthesized from petrochemical by polyols originating from natural products, notably from vegetable oils and animal fats, has been the subject of research projects for a number of decades.

Very recently, however, the polymers industry has intensified its efforts to include the "green products", such as biobased polyols, in applications already available in the market. Examples of such applications include polyurethane foams, elastomers and epoxides.

This book describes the extraction of the natural constituents of several fruits and plants as well as their chemical conversion to polyols. In addition to the chemistry involved in the process, particular emphasis is attributed to their applications.

1
Vegetable Oils, Animal Fats, Carbohydrates and Polyols

1.1 Introduction

This chapter describes polyols in detail, including diols, the chemical components of which are obtained from sources other than crude oil.

The polyols are used in the manufacture of commercial polymers and polyurethanes, for example.

Among the major natural chemicals from which polyols can be derived are:

• Vegetable oils
• Fish oils
• Animal fats
• Carbohydrates

For industrial purposes vegetable oils and carbohydrates are the most approachable sources of chemicals. Work on polyols derived from animal fats can be found in the patent literature [1].

Those products are, quite rightly, described as green products because they originate from natural sources, the production of which humans can control almost at will. They are renewable because, in contrast to crude oil, they originate from non-depletable sources. Their availability is not the monopoly of some countries which possess vast amounts of oil reserves. Agricultural products require the right weather conditions to grow as well as an area large enough for them to be cultivated on.

The first detailed studies on the use of vegetable oils and animal fats in polyurethane technology date back to the late fifties and early sixties.

Among the reasons given for utilizing polyols from natural sources were:

• Since a favorable price differential exists for castor oil over most polyesters, information concerning the properties of various castor urethane foams should be useful to manufacturers and consumers of expanded foams [2].
• Dimer acids are commercially available and are produced by the polymerization of polyunsaturated fatty acids derived from soybean, cottonseed, and linseed oils. Less expensive polyols should result from the condensation of ethylene oxide with dimer acid [3, 4].
• The properties of the castor oil-based foams (PU) are comparable to those of foams obtained from more costly polyols [5].
• A large potential market exists for polyols from natural sources in the rapidly expanding urethane foam industry [6].

In general, the price of oil (Figure 1.1) used to produce the components of polyether and polyester polyols is determined by speculation largely founded on the production policies of the OPEC cartel.

Unfortunately, the pricing of basic carbohydrates or bean oils generally is not much different from that of crude oil.

Soybean oil futures are traded at the Chicago Futures Market, where the price of soybean oil is still lower than that of petroleum (Figure 1.2).

This means that, triglycerides, even if considered renewable sources of chemicals, are subject to speculative pricing the same way crude oil is. However, the difference is that their production is not restricted to only a few countries. Bean oil, or carbohydrate cartels, will be difficult to establish and organize on a global scale. This trading approach does not exclude speculative price hikes similar to those of crude oil.

Figure 1.1 Crude oil (petroleum) price chart (1barrel of crude ~ 140 kg) [7].

Figure 1.2 Soybean oil price variation compared to that of crude oil in USD/ton [7].

Polyols based on renewable raw materials, such as fatty acid triglycerides, sugar, sorbitol, glycerol and dimer fatty alcohols, are already used in diverse ways as raw materials in the preparation of polymer chemicals.

It is claimed that soybean-oil-based polyols cost less than the petroleum polyols they replace, because they require considerably less energy to produce; can be used in a broad range of polyurethane applications; and produce polyurethane products with equivalent or better physical characteristics [8].

In any event, polyols manufactured from petrochemical sources constitute the majority of the polyols, polyesters as well as polyethers used in industry.

Another source of polyols has emerged from the co-polymerization of CO₂ and epoxides [9].

1.2 Sustainability

During the last few years, the term sustainability has been mentioned repeatedly in published articles, speeches, pre...

Table of contents

• Cover
• Table of Contents
• Preface
• 1 Vegetable Oils, Animal Fats, Carbohydrates and Polyols
• 2 Polyurethanes, Polyesters and Epoxies
• 3 Vegetable Oils and Fats
• 4 Chemistry of Triglycerides and Fatty Acids
• 5 Polyols from Triglycerides
• 6 Carbohydrate-Based Polyols
• 7 Biobased Polyols and Their Applications
• Appendix
• Index
• End User License Agreement